############################################################################## # Example file to accompany the CIF dictionary for modulated structures # ############################################################################## # Example: A misfit compound (LaS)1.14 NbS2 # # This is a CIF example corresponding to the modulated structure of # the inorganic misfit layer compound (LaS)1.14NbS2. # Data have been extracted from the already published paper: # # Superspace-Group Approach to the Modulated Structure of the Inorganic # Misfit Layer Compound (LaS)1.14NbS2 # by Sander van Smaalen # J. Phys.: Condens. Matter, (1991), 3, 1247 # # Any line starting with the symbol '#' is considered as a comment. ############################################################################## data_LaSNbS2 _audit_block_code 1997-07-24|LaSNbS2|G.M.| loop_ _audit_link_block_code _audit_link_block_description . 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' _audit_creation_date 1994-07-15 _audit_creation_method 'using a text processor from published results' _audit_update_record ; 1998-05-28 complete revision using cifdic.ms version 0.4 2001-04-20 complete revision using cifdic.ms version 0.47 ; _audit_conform_dict_name cif_ms.dic _audit_conform_dict_version 1.0 #----------------------------------------------------------------------------- # Chemical information #----------------------------------------------------------------------------- _chemical_formula_analytical 'La1.14 Nb S3.14' _chemical_formula_weight 351.93 #----------------------------------------------------------------------------- # Common experimental section. Some of the items present here could be # within the _REFRNCE (reference structure) or _MOD (modulated structure) # data block depending on the specific experimental conditions. #----------------------------------------------------------------------------- _diffrn_symmetry_description ; The whole diffraction pattern shows orthorhombic symmetry. The following extinction rules were detected: hklm h+k+m=odd hklm h+l =odd hklm k+l+m=odd hk0m h+k =odd hk0m m =odd Extinction rules are compatible with the superspace groups: P:Fmmm:-11s(\a,0,0) P:Fm2m:-1-1s(\a,0,0) ; #----------------------------------------------------------------------------- # Superspace group #----------------------------------------------------------------------------- _space_group_ssg_name_WJJ 'P:F m 2 m:-1 -1 s' #----------------------------------------------------------------------------- # The next items are neccessary, basically, to check the # consistency of the CIF. An extra Miller index is expected. #----------------------------------------------------------------------------- _exptl_crystal_type_of_structure 'comp' _cell_subsystems_number 2 _cell_modulation_dimension 1 _cell_reciprocal_basis_vect_number 4 loop_ _cell_subsystem_code _cell_subsystem_description _cell_subsystem_matrix_W_1_1 _cell_subsystem_matrix_W_1_4 _cell_subsystem_matrix_W_2_2 _cell_subsystem_matrix_W_3_3 _cell_subsystem_matrix_W_4_1 _cell_subsystem_matrix_W_4_4 NbS2 '1st subsystem' 1 0 1 1 0 1 LaS '2nd subsystem' 0 1 1 1 1 0 #----------------------------------------------------------------------------- # Extended reciprocal cell. Order is important. It defines the order of # Miller indices. #----------------------------------------------------------------------------- _cell_reciprocal_basis_description ; a1*,b1*,c1* (reciprocal basis spanning the reciprocal basis of the first subsystem), a2* reciprocal axis corresponding to the second subsystem. ; _diffrn_radiation_source 'X-ray tube' _diffrn_reflns_satellite_order_max 2 loop_ _diffrn_reflns_class_description _diffrn_reflns_class_code 'main reflections' 'Main' 'common main reflections' 'Com' 'NbS2 part' 'NbRefls' 'LaS part' 'LaRefls' 'first-order satellites' 'Sat1' 'second-order satellites' 'Sat2' # In the next entry \s stands for sigma. _reflns_observed_criterion 'I>2.5\s(I) for any reflection class' _reflns_number_observed 860 loop_ _reflns_class_number_gt _reflns_class_code 584 'Main' 226 'Sat1' 50 'Sat2' #----------------------------------------------------------------------------- # Computing section #----------------------------------------------------------------------------- _computing_structure_refinement 'COMPREF (Petricek)' #----------------------------------------------------------------------------- # List of reflections. #----------------------------------------------------------------------------- loop_ _refln_index_h _refln_index_k _refln_index_l _refln_index_m_1 _refln_F_meas _refln_F_calc _refln_F_sigma _refln_observed_status _refln_scale_group_code # Next question marks are included for consistency ? ? ? ? ? ? ? ? ? # More reflections here... #----------------------------------------------------------------------------- #Items concerning publication data #----------------------------------------------------------------------------- loop_ _citation_id _citation_title _citation_journal_abbrev _citation_journal_volume _citation_page_first _citation_page_last _citation_year primary ; Superspace-group approach to the modulated structure of the inorganic misfit layer compound (LaS)1.14NbS2 ; 'J. Phys.:Condens. Matter' 3 1247 1263 1991 loop_ _citation_author_citation_id _citation_author_name primary 'van Smaalen, S.' ########################## End of common data ########################## ############################################################################## # Common items concerning the unmodulated (basic, average) refinement ############################################################################## data_LaSNbS2_REFRNCE _audit_block_code 1997-07-24|LaSNbS2|G.M.|_REFRNCE loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' . 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' loop_ _diffrn_reflns_class_description _diffrn_reflns_class_code 'main reflections' 'Main' 'common main reflections' 'Com' 'NbS2 part' 'NbRefls' 'LaS part' 'LaRefls' 'first-order satellites' 'Sat1' 'second-order satellites' 'Sat2' loop_ _refine_ls_class_R_factor_gt _refine_ls_class_code 0.071 'Main' 0.075 'Com' 0.097 'NbRefls' 0.051 'LaRefls' ############### End of unmodulated structure common data ############### ############################################################################## # Items concerning the reference (basic, average) structure of the # first subsystem NbS2 ############################################################################## data_LaSNbS2_REFRNCE_NbS2 _audit_block_code 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' . 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' _cell_length_a 3.310 _cell_length_b 5.793 _cell_length_c 23.043 _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 441.85 _symmetry_cell_setting orthorhombic _symmetry_space_group_name_H-M 'F m 2 m' ########## End of reference structure first subsystem data ############ ############################################################################## # Items concerning the reference (basic, average) structure of the # second subsystem LaS ############################################################################## data_LaSNbS2_REFRNCE_LaS _audit_block_code 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' . 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' _cell_length_a 5.828 _cell_length_b 5.793 _cell_length_c 11.522 _cell_angle_alpha 90.00 _cell_angle_beta 90.00 _cell_angle_gamma 90.00 _cell_volume 389.00 _symmetry_cell_setting orthorhombic _symmetry_space_group_name_H-M 'C m 2 a' ######### End of reference structure second subsystem data ############ ############################################################################## # Common items concerning the modulated structure ############################################################################## data_LaSNbS2_MOD _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' . 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' loop_ _diffrn_reflns_class_description _diffrn_reflns_class_code 'main reflections' 'Main' 'common main reflections' 'Com' 'NbS2 part' 'NbRefls' 'LaS part' 'LaRefls' 'first-order satellites' 'Sat1' 'second-order satellites' 'Sat2' _refine_ls_R_factor_all 0.064 loop_ _refine_ls_class_R_factor_gt _refine_ls_class_code 0.057 'Main' 0.074 'Com' 0.064 'NbRefls' 0.046 'LaRefls' 0.112 'Sat1' 0.177 'Sat2' ################ End of modulated structure common data ################ ############################################################################## # Items concerning the modulated structure of the first-subsystem ############################################################################## data_LaSNbS2_MOD_NbS2 _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_NbS2 loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' . 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_LaS 'modulated structure (2nd subsystem)' _space_group_ssg_name_WJJ 'P:F m 2 m:-1 -1 s' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_refinement_flags _atom_site_displace_modulation_flag Nb1 0 -0.0751(6) 0 Uani S yes S1 0 0.2583(8) 0.0678(2) Uani S yes #----------------------------------------------------------------------------- # Modulation parameters #----------------------------------------------------------------------------- _refine_ls_mod_func_description ; Displacive modulation. Fourier series. ; #----------------------------------------------------------------------------- # Modulation wave vector. Here is expressed the modulation wave vector # a2*, in the three-dimensional reciprocal basis of the first subsystem. #----------------------------------------------------------------------------- loop_ _cell_wave_vector_seq_id _cell_wave_vector_x 1 0.568 loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_description 1 0.568 'First harmonic' 2 1.136 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Nbz1 Nb1 z 1 Nbx2 Nb1 x 2 Nby2 Nb1 y 2 Sx1 S1 x 1 Sy1 S1 y 1 Sz1 S1 z 1 Sx2 S1 x 2 Sy2 S1 y 2 Sz2 S1 z 2 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin Nbz1 -0.0006(2) 0. Nbx2 0. 0.0078(17) Nby2 -0.0014(7) 0. Sx1 0. -0.0134(85) Sy1 -0.0022(12) 0. Sz1 0.0014(14) 0. Sx2 0. -0.0129(27) Sy2 -0.0073(27) 0. Sz2 -0.0012(3) 0. ########## End of modulated structure first subsystem data ############ ############################################################################## # Items concerning the modulated structure of the second subsystem ############################################################################## data_LaSNbS2_MOD_LaS _audit_block_code 1997-07-24|LaSNbS2|G.M.|_MOD_LaS loop_ _audit_link_block_code _audit_link_block_description 1997-07-24|LaSNbS2|G.M.| 'common experimental and publication data' 1997-07-24|LaSNbS2|G.M.|_REFRNCE 'reference structure (global data)' 1997-07-21|LaSNbS2|G.M.|_MOD 'modulated structure (global data)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_NbS2 'reference structure (1st subsystem)' 1997-07-21|LaSNbS2|G.M.|_MOD_NbS2 'modulated structure (1st subsystem)' 1997-07-24|LaSNbS2|G.M.|_REFRNCE_LaS 'reference structure (2nd subsystem)' . 'modulated structure (2nd subsystem)' _space_group_ssg_name_WJJ 'P:C m 2 a:-1 -1 1' loop_ _atom_site_label _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_refinement_flags _atom_site_displace_modulation_flag La1 0 0.0 0.32633(5) Uani S yes S2 0 0.5086(22) 0.3003(2) Uani S yes _refine_special_details ; y-coordinate of La1 atom was not refined to fix the origin ; #----------------------------------------------------------------------------- # Modulation parameters #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Modulation wave vector. Here is expressed the modulation wave vector # a1*, in the three-dimensional reciprocal basis of the second subsystem. #----------------------------------------------------------------------------- _refine_ls_mod_func_description ; Displacive modulation. Fourier series. ; loop_ _cell_wave_vector_seq_id _cell_wave_vector_x _cell_wave_vector_z 1 1.761 0.5 loop_ _atom_site_Fourier_wave_vector_seq_id _atom_site_Fourier_wave_vector_x _atom_site_Fourier_wave_vector_z _atom_site_Fourier_wave_vector_description 1 1.761 0.5 'First harmonic' 2 3.522 1.0 'Second harmonic' loop_ _atom_site_displace_Fourier_id _atom_site_displace_Fourier_atom_site_label _atom_site_displace_Fourier_axis _atom_site_displace_Fourier_wave_vector_seq_id Lax1 La1 x 1 Lay1 La1 y 1 Laz1 La1 z 1 Lax2 La1 x 2 Lay2 La1 y 2 Laz2 La1 z 2 Sx1 S2 x 1 Sy1 S2 y 1 Sz1 S2 z 1 Sx2 S2 x 2 Sy2 S2 y 2 Sz2 S2 z 2 loop_ _atom_site_displace_Fourier_param_id _atom_site_displace_Fourier_param_cos _atom_site_displace_Fourier_param_sin Lax1 0. -0.0010(22) Lay1 0.0174(4) 0. Laz1 -0.0005(3) 0. Lax2 0. 0.0144(7) Lay2 0.0001(14) 0. Laz2 0.0008(3) 0. Sx1 0. 0.0059(70) Sy1 0.0081(16) 0. Sz1 0.0009(12) 0. Sx2 0. -0.0030(30) Sy2 0.0002(56) 0. Sz2 0.0007(10) 0. ######### End of modulated structure second subsystem data ############